/*
 * Copyright (c) 2007, Technische Universitaet Berlin
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met:
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright 
 *   notice, this list of conditions and the following disclaimer in the 
 *   documentation and/or other materials provided with the distribution.
 * - Neither the name of the Technische Universitaet Berlin nor the names 
 *   of its contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE 
 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/**
 * @author Philipp Huppertz <huppertz@tkn.tu-berlin.de>
 */


#include <errno.h>
#include <iostream>
#include <unistd.h>

#include "basecomm.h"

BaseComm::BaseComm()
{
}


BaseComm::~BaseComm()
{
}

/* all count bytes must be read before returning - blocking in that way... */
int BaseComm::readFD(int fd, char *buffer, int count, int *err)
{
    int actual = 0;
    while (count > 0)
    {
        int n = read(fd, buffer, count);
        if (n == -1)
        {
            *err = errno;
            return -1;
        }
        if (n == 0)
        {
            return actual;
        }
        count -= n;
        actual += n;
        buffer += n;
    }
    return actual;
}

/* all count bytes must be written before returning - blocking in that way... */
int BaseComm::writeFD(int fd, const char *buffer, int count, int *err)
{
    int actual = 0;
    while (count > 0)
    {
        int n = write(fd, buffer, count);
        if(n == -1)
        {
            if(errno != 0) {
                *err = errno;
                return -1;
            }
            else {
                // looks like a temporary glitch
                n = 0;
            }
        }
        count -= n;
        actual += n;
        buffer += n;
    }
    return actual;
}
